Dynamics of an oscillating wave surge converter: an analysis on the influence of the bottom slope

Abstract

The Oscillating Wave Surge Converter represents a technology with great potential for generating electricity from ocean waves, promoting energy continuously throughout a day. Its development is on a pre-commercial scale and has been encouraging several companies and institutions to invest in the improvement and study of this conversion system. Simulations in Computational Fluid Dynamics are very important tools for the development of these converters, since they provide essential details for the analysis of the variables that influence the system. In this context, the present work uses the Large Eddy Simulation modeling to study the influence of the bottom slope on the device dynamics, which is performed using the OpenFOAM v.4.1 computational code and its extension OlaFlow. The model used in the analysis is two-dimensional and based on the Wall-Adapting Local Eddy-Viscosity methodology, while a structured mesh is applied. Through a detailed analysis, it was observed that the converter hydrodynamics is strongly influenced by the bottom slope, which is responsible for the intensification of the captured power in regions with slopes lower than 5º, and for the power decrease in cases where the slope exceeds 15º. Significant increases in slope can cause a decrease up to 28% in the converter excitation torque, significantly affecting its performance in electric power generation.